Lever ring having a slanted flat strip

ABSTRACT

The invention comprises a lever ring to be connected to a body ( 20 ) by means of a seam and for receiving a closure layer ( 1 ) that has been connected by means of sealing onto the edge and which bridges an inner space of the lever ring and, in the seam-connected condition, closes the body ( 20 ), wherein the lever ring comprises a continuous flat web ( 3   a,    3   b,    3   c ), which radially outwardly changes into a lid rim ( 2 ) of the lever ring, a continuous groove (n 1 , N 2 , N 3 ) extending between the lid rim and the flat web, the flat web is suited for connecting the edge of the closure layer by means of sealing and extends at an angle (α 1, α2, α3 ) differing from zero with respect to the plane of a closure layer ( 1 ) being connected by means of sealing in this fashion the holding force on the flat web is increased.

The invention is concerned with a special shaping of a lever ring foroptimizing the action of force of the closure layer that acts as anarchable membrane, the action of force being optimized in a bondingstrip, in particular a sealing seam, in order to increase the toughnessor stability of the seam with respect to an existing internal pressure,with the package being closed. Other actions of force can also be betterabsorbed by this.

Starting from the customary design of a lever ring, cf. e.g. EP-A 408268 (CMB) or WO-A 97/49510 (Impress), FIG. 4 thereof, or GB-A 2 022 474(Swiss Aluminium), which comprises a lid rim at the outside and ahorizontally aligned flat web at the inside, the hold (the bonding) of amembrane-like sealing film sealed onto this flat web is to be improved.In a normal condition, the lever ring is at first closed with a sealingfolm at the inside. Due to this, a continuous sealing seam of a certainwidth is formed, which extends clearly on the flat web. Here, theholding forces for the closure layer are applied, which is slightlyarched by the developing internal pressure, which puts a stress on thesealing seam at the bonding site beginning at the inside in a notch-likefashion, but preferably not that high that a limit of cohesive forces isexceeded.

Inclined lid rims have also become known in the remaining prior art, sofar in the case of push-in lids, cf. in this connection DE-A 28 30 614(Officine Monfalconese) or WO-A 00/21840 (Brasilata Metallicas).

The invention starts from the technical problem of increasing a holdingforce on the flat web without having to implement additional changes inthe consistency or the strength or width of the sealing seam.

The invention suggests not to align the flat web substantiallyhorizontally, but to have it extend in an inclined fashion at an angle,that plane being used as the reference plane which results in the caseof a closure layer that is connected by means of sealing. Due to this,the flat web is upwardly angled, a large range of angles being at firstpossible, between more than 10° and up to substantially 90°, based onsaid plane. However, the closure layer must not already be connected bymeans of sealing, but the lever ring is also circumscribed and subjectedto stress so that the closure layer as such has not been connected bymeans of sealing as yet (claim 1), but hypothetically serves as ameasure as to which plane is used as a comparative plane. This plane canalso be considered as a “horizontal” (claim 2), if the lever ring isplaced onto a surface.

Ranges of the angular extension (of the inclined extension) of the flatweb of more than 10°, in the range of between 25° and 35° and between40° and 60° or, however, substantially vertically or between 80° and 90°(claims 3 to 7) are preferred.

If the flat web is inclined, a wedge-shaped groove results between acontinuous wall which, in its capacity as the core wall, leads to thecontainer rim, and the inclined flat web. This wedge-shaped design hastwo walls that do not extend in parallel and a rounded bottom area whichextends as a continuous groove and forms the lowermost point of thelever ring, seen in the axial direction.

The container rim is a structure that extends around the circumferenceand arches towards the outside and downwards and is suited for theseaming of the lever ring to a body hook of a body. A double seam can beused as the seam. Mostly, the lever ring is at first sealed with theclosure layer, delivered in this prefabricated form and the body isfilled with the products to be packaged at the filling plant in order tosubsequently cover it jointly with the lever ring and the closure layerand then to form the double seam at the edge. At least one or severalshackles may be provided at a suitable point on the edge of the closurelayer, which serve(s) for peeling off and starting to undo the sealingseam at this point. The entire sealing seam is continuously undonearound the circumference and opens the inner space in order to grantaccess to the packaged product.

A curling of the edge may be provided on the inner side of the flat webthat is aligned in an inclined fashion (claim 9). It forms a deflectionpoint for the closure layer which is aligned as of this inner curling ina plane position (without stress by the internal pressure), whereas theedge of this closure layer is inclined in accordance with the alignmentof the flat web and extends thereon across the sealing seam (the bondingstrip) in a peelably attached fashion. Due to this deflection, pressureforces within the closed container, which act on the closure layer, areat least partly converted to such forces which are developed as tensileforces in the extension direction of the sealing seam. A substantiallygreater force can be applied in this direction, since the entire widthof the sealing seam withstands this tensile force. Pure tensile forcesthat are developed vertically to the sealing seam and that are e.g.present during the peeling off or opening of the closure can be reducedfor the closed condition. Due to this, the point in time can be delayedat which the cohesive effect of the sealing seam breaks, the so-calledcohesive failure, which, instead of at 25 N, can be shifted to higherranges, up to 40 N. In the case of substantially 90° (claim 6) 50 N areeven achieved up to failure.

Metallic films can be used as a closure layer, but also plastic films,which are sealed in the marginal area. Compound films (several layers)or metallized films are likewise possible, which must be applied bymeans of sealing. A sealing strip on the flat web, which is separatelyapplied offers itself as a sealing surface, if a metallic closure layeris used as the film. It has a substantial width, which amounts to morethan half, preferably substantially the entire extension of the flat web(claim 12).

If a flat web aligned substantially vertically (to the horizontal planeof the closure layer) is used, the internal edge curling can evenaxially project above the upper side of the lid rim for the seam (claim13).

Examples explain and supplement the invention.

FIG. 1 illustrates a cutout from a lever ring which is shown as an axialsection.

FIG. 2 illustrates an alternative embodiment with a flat web that isdifferently inclined.

FIG. 3 illustrates a third embodiment with a flat web which againextends again in a different way, once more at a flatter inclination.

FIG. 4 a, FIG. 4 b illustrate differences between tensile forces andshearing forces at a pressure load from the interior to the inner sideof the closure layer 1, the pressure load being designated with F_(i).

A cut out of a lever ring is shown in FIG. 1, which is closed with afilm 1 in the closed condition, which may be of many alternativedesigns, it can e.g. be made of plastic material or metal or a compositeof such layers.

A lid rim 2 is provided in the marginal area of the lid closed with thefilm, which is of a substantially U-shaped shape. A U-shaped shape witha different orientation is found in a groove N1 which is formed betweenthe inner wall of the lid rim as the chuck wall and a flat web 3 a whichextends upwards. The edge area of the closure layer 1 is closed with asealing layer that is not especially represented here on the axial outerside of the flat web. As regards the design of the sealing layerreference is made to FIG. 4 b by way of example, which shows thissealing layer 30 as an adhesive layer, e.g. of adhesive or anothersuitable, adhesive and food-compatible material.

The body is symbolically shown as a trough 20 which has an obliquelyprojecting edge 21 over which, upon closing, the lid rim 2 is slipped inorder to be subsequently converted into a double seam by means of aclosing machine and a seam roller so that the body 20 is thus closed.The container wall 22 of the body is shown in a vertically projectingfashion, which defines the height of the volume of the body 20 to bereceived.

An inner curling 4 is provided at the inner side of the flat web 3 a,the exact design of which can also be gathered from FIG. 4 a, 4 b. Itavoids risks of cutting and provides for a deflection u of the closurelayer 1 between a sealing section in its marginal area 1 b and a planesection which projects above the entire inner space within the lid rim 4in a self-supported fashion and closes it.

The inclination of the flat web 3 a is indicated with approx. 90° as theangle α1 in the example of embodiment of FIG. 1. The alignment of theflat web is thus substantially vertically to the plane which is given bythe inner area of the closure layer 1. In this example, the inner rim 4slightly projects axially beyond the upper side of the external lid rim2 so that the closure layer 1 projects upwards beyond this outer side.

An alternative inclination α2 is shown for the flat web 3 b in FIG. 2.This angle is in the range between 40° and 60°, oriented by thedescribed plane of the membrane 1 which is drawn very thinly here withthe thickness d. As opposed to the thickness of this closure layer 1,the sheet metal in the lever ring is designed thicker so that the formedgeometries are maintained during normal use with the exception of thereshaping of the lid rim 2 when forming the seam with the body hook 21of the body 20.

The smaller inclination α2 that is drawn in FIG. 2 as compared with FIG.1, based on the flat web 3 b, results in another cross-sectional shapeof the circumferential groove N2 which extends substantially inwedge-shaped fashion and has a rounded groove bottom. This groove bottomforms the lowermost point of the lever ring which, as such, can bedesigned in a round, oval, oblong, or rectangular shape with slightlyrounded inner corners, if the formation of an inner curling 4 is alsomade possible in these inner corner areas.

A still further design is shown in FIG. 3, where a flatter alignment α3of the flat web 3 c is selected in the range between 25° and 35°. Allother features of the preceding description of FIG. 2 are also compliedwith. Here, as well, the inner curling 4 serves as a deflection pointfor the membrane in the area between the sealing point 30, 1 b thatextends circumferentially and the inner surface 1 for covering theopening within the inner curling 4.

The angle α3 can be further reduced up to about 10° in further examples,which are not separately represented, however, it should be more than 0°and thus form an oblique (inclined) design as compared with thedescribed plane of the closure membrane 1.

Due to the different orientation of the flat web which is nothorizontally aligned due to its name, but is of a flat design across aclear width in order to produce a flat sealing seam onto which themembrane can be attached sufficiently well and tightly, there aredifferent designs for the shape of the circumferential groove N2, N3with a wall which, in each case, extends more flatly towards the inside,but with a substantially equal slope of the core wall towards the lidrim 2.

Due to the inclination of the flat web which is shown by way of exampleby means of the examples α, α2, α3, a system according to FIG. 4 b isobtained. An internal pressure on the self-supporting inner surface ofmembrane 1 is deflected by the inner rim 4 and provides for a tensileforce in the sealing area 30. The entire width of the sealing seam 30,the section of which is represented in FIG. 4 b, can withstand thistensile force z, namely better than if a horizontal alignment of theflat web according to FIG. 4 a were chosen. Here, the pressure forceF_(i) acts on the membrane 1 so that a notch effect x is formed at thepoint 31 of the sealing seam 30 due to a vertical tensile force X,which, due to the forces applied substantially vertically to theextension of the sealing strip 30, results more easily in a loss of thecohesive effect and thus in a cohesive failure than it was described inFIG. 4 b.

The greater the inclination of the flat web 32 is, the greater is theconversion of the forces extending vertically to the sealing seam 30according to FIG. 4 a to such forces that can be called per se “shearingforces”. Peeling forces (vertical tensile forces) are converted to suchforces extending in parallel to 30, which can be better absorbed by theentire width of the sealing seam 30 according to FIG. 4 b than thetensile forces X according to FIG. 4 a, which have a notch effect.

1. A lever ring for seaming to a body (20) and for receiving a closurelayer (1) affixed with an edge by means of sealing and for bridging aninner space of the lever ring, to close the body (20) in aseam-connected position, wherein (i) the lever ring comprises acontinuous flat web (3 a, 3 b, 3 c) which radially outwardly changesinto an edge rim (2) of the lever ring, a continuous groove (N1, N2, N3)extending between the edge rim and the flat web; (ii) the flat web issuitable for connecting an edge of the closure layer by sealing, andextends with respect to a plane of the closure layer (1), that has beenconnected by such sealing, at an angle (α1, α2, α3) differing from zero.2. A lever ring for seaming to a body (20) and for receiving a closurelayer (1) affixed with an edge by means of sealing and for bridging aninner space of the lever ring, to close the body (20) in aseam-connected position, wherein (i) the lever ring comprises acontinuous flat web (3 a, 3 b, 3 c) which radially outwardly changesinto an edge rim (2) of the lever ring, a continuous groove (N1, N2, N3)extending between the edge rim and the flat web; (ii) the flat webextends upwardly inclined from a horizontal plane and is provided withan inner curling (4) on its radially inner end so that a closure layer(1) affixed to it by sealing (30) introduces a substantial forcecomponent (z) into a sealing seam (30), so that the force componentextends in an extension direction of the sealing seam, upon a pressureforce (F_(i)) acting vertically to a plane of extension of the closurelayer.
 3. The lever ring according to claim 2, wherein the anglediffering from zero is between substantially 10° and substantially 90°.4. The lever ring according to claim 2, wherein the angle (α2) isbetween substantially 40° and 60°.
 5. The lever ring according to claim2, wherein the angle (α2) is between substantially 25° and 35°.
 6. Thelever ring according to claim 2, wherein the angle (α2) is betweensubstantially 80° and 90°.
 7. The lever ring according to claim 2,wherein the angle differing from zero extends substantially verticallyto the extension of the plane of the closure layer (1).
 8. The leverring according to claim 2, wherein said receiving of the closure layeris a sealing of an edge of the closure layer by a sealing strip (30) onthe flat web (3 a, 3 b, 3 c) which sealing strip extendscircumferentially.
 9. The lever ring according to claim 2, wherein theflat web comprises radially inwards an inner curling (4).
 10. The leverring according to claim 2, wherein the closure layer extends on theinner curling (4) and is deflected (u) so that an edge strip (1 b) isformed, which extends at an angle differing from zero, with respect tothe plane of the closure layer (1) in the inner area of the lever ring.11. The lever ring according to claim 2, wherein the closure layer isformed as a membrane made of one or more materials selected from a groupconsisting of: plastic, sheet metal, metal foil, and compound foil. 12.The lever ring according to claim 2, wherein the sealing seam (30) as astrip extending circumferentially has a substantial width on theextension of the flat web (3), this width being more than half the widthof the flat web.
 13. The lever ring according to claim 2, wherein theinner curling axially projects above an upper side of the lid rim (2)with an alignment of the flat web (3 a) that projects steeply upwards.14. The lever ring according to claim 2, wherein the groove (N1, N2, N3)is of a wedge-shaped design with a rounded bottom and is formed betweena chuck wall extending towards the lid rim (2) and the flat web (3 a, 3b, 3 c) that is oriented in an inclined fashion.
 15. The lever ringaccording to claim 1, wherein the angle differing from zero is betweensubstantially 10° and substantially 90°.
 16. The lever ring according toclaim 1, wherein the angle (α2) is between substantially 40° and 60°.17. The lever ring according to claim 1, wherein the angle (α2) isbetween substantially 25° and 35°.
 18. The lever ring according to claim1, wherein the angle (α2) is between substantially 80° and 90°.
 19. Thelever ring according to claim 1, wherein the angle differing from zeroextends substantially vertically to the extension of the plane of theclosure layer (1).
 20. The lever ring according to claim 1, wherein saidreceiving of the closure layer is a sealing of an edge of the closurelayer by a sealing strip (30) on the flat web (3 a, 3 b, 3 c) whichsealing strip extends circumferentially.
 21. The lever ring according toclaim 1, wherein the flat web comprises radially inwards an innercurling (4).
 22. The lever ring according to claim 1, wherein theclosure layer extends on the inner curling (4) and is deflected (u) sothat an edge strip (1 b) is formed, which extends at an angle differingfrom zero, with respect to the plane of the closure layer (1) in theinner area of the lever ring.
 23. The lever ring according to claim 1,wherein the closure layer is formed as a membrane made of one or morematerials selected from a group consisting of: plastic, sheet metal,metal foil, and compound foil.
 24. The lever ring according to claim 1,wherein the sealing seam (30) as a strip extending circumferentially hasa substantial width on the extension of the flat web (3), this widthbeing more than half the width of the flat web.
 25. The lever ringaccording to claim 1, wherein the inner curling axially projects abovean upper side of the lid rim (2) with an alignment of the flat web (3 a)that projects steeply upwards.
 26. The lever ring according to claim 1,wherein the groove (N1, N2, N3) is of a wedge-shaped design with arounded bottom and is formed between a chuck wall extending towards thelid rim (2) and the flat web (3 a, 3 b, 3 c) that is oriented in aninclined fashion.